Start by taking everything under 400mm out of your list. For birding, you want all the reach you can get.
Also, remember that the 100-400 is also f5.6 at 400mm, thus probably not worth trying to pair it with a converter on that camera.
Now I am a Nikon shooter, so have no direct experience with any of the lenses you mention, but for me the choise is between the 400 f5.6 and the Tamron 150-600 G2.
For birding, fast AF is far more important than IS, and you will need high shutter speeds to freeze subject motion anyway. For things not moving, use a tripod or beanbag.